The Importance of Proper Protein and Calorie Intake in Critically Ill Patients – Insights from Recent Comparisons

Intake of Macronutrients in Practice vs. ESPEN Standards

Nutritional therapy can influence treatment outcomes in critically ill individuals hospitalized in ICUs, according to available data. An international team of intensive care experts performed a prospective observational cohort study to assess current practices in European settings and their significance for patients. For patients hospitalized in ICUs for ≥5 days, whose health was monitored for 90 days, the intake of macronutrients from enteral and parenteral nutrition and other non-nutritional components during the first 15 days in the ICU was compared with nutrition guidelines issued by the European Society for Clinical Nutrition and Metabolism (ESPEN).

The study examined the relationships between 3 categories of nutrition:

• Low energy intake (<10 kcal/kg) and low protein intake (<0.8 g/kg)
• Moderate energy intake (10–20 kcal/kg and 0.8–1.2 g protein/kg)
• High energy intake (>20 kcal/kg and >1.2 g protein/kg)

and the rate of 90-day mortality or successful weaning from mechanical ventilation.

A total of 1172 patients with a median APACHE II score of 18.5 were included in the study. The median length of ICU stay was 10 days, and 74% of patients could be weaned off mechanical ventilation. During the 90-day period, 24% of patients died. The studied patients reached an average of 83% of the recommended energy intake according to ESPEN standards and 65% of the recommended protein intake.

The best clinical outcomes were achieved with moderate energy intake (10–20 kcal/kg) and protein intake (0.8–1.2 g/kg). This level of energy intake is also associated with the lowest risk of death. The study did not demonstrate that high energy intake and high protein intake provided significant further improvement in the clinical condition of patients.

Oral Food Intake vs. Artificial Nutrition

Comparing these two methods of calorie and protein intake for ICU patients is another crucial, yet not often analyzed aspect of treatment for critically ill individuals. A Belgian study from 2021 focused on the comparison of energy and protein intake in patients dependent on artificial nutrition (enteral or parenteral) and those consuming food orally. The authors compared the difference between the recommended energy and protein intake based on the patient's weight and the actual intake of energy and protein in individuals hospitalized in the ICU for ≥3 days.

In the observed group of 253 patients with an average age of 67 years, 126 consumed food orally, 40 had a combination of oral food and parenteral or enteral nutrition, and 87 were fed only parenterally or enterally. Overall, all these patients consumed an average of 14.3 kcal/kg/day and 0.53 g protein/kg/day. In the group with exclusively oral nutrition, a total energy intake of 9.7 kcal/kg/day and protein intake of 0.35 g/kg/day was found. Patients from this group who were treated in the ICU for at least 7 days (n = 37) did not achieve sufficient energy intake in 51% of cases and sufficient protein intake in 94% of cases (i.e., at least 80% of the recommended daily intake of calories and protein).

Nutrition provided through the oral route thus offers significantly lower energy and protein intake for ICU patients compared to artificial nutrition or a combination of artificial nutrition and oral food.

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Sources:
1. Matějovič M., Huet O., Dams K. et al. Medical nutrition therapy and clinical outcomes in critically ill adults: a European multinational, prospective observational cohort study (EuroPN). Crit Care 2022 May 18; 26 (1): 143, doi: 10.1186/s13054-022-03997-z.
2. Rougier L., Preiser J. C., Fadeur M. et al. Nutrition during critical care: an audit on actual energy and protein intakes. J Parenter Enteral Nutr 2021 Jul; 45 (5): 951–960, doi: 10.1002/jpen.1962.